The model railroading industry is seeing a rapid and almost overwhelming advancement in technology. The introduction of new electronic throttles in the 1960's was the start of tremendous creativity that has touched almost every part of model railroading products including a variety of command control systems, conventional control systems, on-board sound, speed control, accessory operation, lighting effects, computer interaction, website up grades and downloads, bi-directional communication, talking trains, singing trains, on-board cameras, automatic operation, etc. Along with this welcome and exciting creativity, issues regarding compatibility, cost, and obsolescence have appeared. In this rapidly advancing innovative market, the end user can become confused or overwhelmed by the variety and jargon related to these emerging technologies. For many years the motor in all HO locomotives simply connected to track pickup and the power was provided by a variable DC power pack. Making a model locomotive go fast or slow was simply a matter of applying more voltage to the track and changing direction was accomplished by changing the polarity on the track. Today, end users need more than a basic understanding of electricity and electronics. With modern command control systems, they need to understand basic digital technology, signal transmission, programming CV's, trouble shooting motor drives and decoders, ID numbers, etc. Technology has changed so much over that last twenty-five years and has so many contributors that a detailed list of inventions and inventors would take pages. Regarding this invention, a brief description of the relevant subjects and prominent prior art contributors are described below.
Command Control started with Lionel's high frequency electronic set in 1946 to control ten different functions of the locomotive and rolling stock including reversing the direction of the locomotive. There was no real advance in train control until the 1970's when transistor technology opened up new possibilities. A number of viable and commercial command control systems were introduced in the 1980's but serviced a small segment of the market due to its technological complexities and confusion over the variety of methods being sold. In 1994, the NMRA established a preferred method of transmitting digital signals that became the standard for the Digital Command Control in the US.
Command control took a different path for 60 hertz AC powered trains when Lionel introduced their Train Master Command Control (TMCC) system in 1994. This method transmits radio signals to receivers in the locomotives to control speed, direction and features independently for each train. AC powered trains like Lionel three-rail O'Gauge and two-rail American Flyer S'Gauge trains have continued to use the same technology first developed in 1906. Because of their universal AC/DC motors and power pickup methods, AC powered trains require greater power and produce more electrical noise than the more efficient DC powered trains introduced in the 1950's. For this reason, direct transmission of electrical control signals down the track for AC powered trains has been more difficult than for DC powered trains. Although NMRA DCC has been tried with AC three-rail, it has not proved very reliable or popular. The TMCC system avoids the noise problems of AC powered trains by direct radio transmission. QSI has developed a digital transmission method down the track using plus and minus DC superimposed on AC track power to overcome this noisy environment, which is described in U.S. Pat. No. 4,914,431. Later, QSI proposed a command control system using the positive and negative lobes of AC power to transmit digital signals; this method is described in our U.S. Pat. No. 5,773,939. In 2000, MTH introduced their Digital Command System (DCS) with high-speed digital signals superimposed on the AC track.
Speed Control: Methods for electric motor control and servo loops to maintain motor speed at a desired setting have been available from the early 1960's. This technology has had many applications both inside and outside model railroading. For instance, this technology was applied to magnetic tape drives by TELIX and Storage Technology Company (STC) in the 70's and 80's and has found popular use for military and computer peripheral applications. A reference book for motor control entitled Electric Motors & Electronic Motor-Control Techniques by Irving M. Gottlieb (1976) describes a number of electronic motor control techniques including servo-based methods. Back EMF and tachometer based feedback servo motor control applications are not new.
The first use I am aware of in model railroading was with servo based Back EMF throttles developed by Paul Mallery in 1983, and also by on Ron Sokol who developed and sold a Back EMF throttle under the trademark: Loggers Supply Company” in the 70's. Mallery in his Electrical Handbook for Model Railroads, Vol. 2, described the basic concept of a servo-type feedback control system as follows.
“The most precise method of motor control is to measure speed and compare the voltage representing actual speed with that of the speed control to generate an error signal which then corrects any deviation from the speed desired by the engineer. The essential elements of such a control circuit are shown in block form in FIG. 16-19. This is a true servo control and requires careful design.”
Mallery's FIG. 16-19 is reproduced here as FIG. 62. Mallery goes on to describe a number of ways that motor speed can be measured including using the motor's back EMF from DC can-type motors. Although Mallery was interested in showing how servo-type speed control can be utilized in a throttle design, the basic concept of motor control can easily be extended to on-board control systems. In this case, the speed reference is set either by an analog remote control signal or by digital transmission of the desired speed reference to the on-board servo system. In particular, the Trix company designed an IC chip for on-board digital control, which included BEMF speed detection and motor speed control in the 1980's. Other companies have produced similar products in the 1990's including Zimo and Lenz Co., which have been selling their Load Compensated DCC on-board controllers since 1996. These decoders allow operators to set any speed they desire for each of the DCC speed steps. Sending data bit sequences down the track to set an on-board speed reference to a desired speed for a servo-type speed control circuit to maintain that desired speed is not new.
Bi-Directional Communication: Bi-directional communication is described in Mallery's Electrical Handbook for Model Railroads, Vol. 2, for servo-type transistor throttles. FIG. 62 shows Mallory's speedometer feedback of the locomotive's speed to the controller in order to maintain constant speed. Since command control is similar to data transmissions between digital components like between computers and printers and other digital accessories, or between computers and the Internet, etc., it was a natural extension to add digital bi-directional communication to digital command control. In particular, Mallery describes a digital system in his chapter on command control where bi-directional signals are sent from the locomotive back to the cab or throttle. Mallery describes auxiliary commands that might be added to command control as follows.
In FIG. 17-9, four command pulses are shown as assigned to auxiliary devices such as an on-board sound generator, a unit to turn on, off or dim the headlight and control of uncoupling. The latter would be an enormous benefit on a switching locomotive. Also, as indicated at the right in FIG. 17-9, spaces can be reserved for pulses generated on the locomotive to send information back to the cab. Among the best uses of such information are the current being drawn, scale speed, an excessive temperature alarm, and cab signals.
Mallery's FIG. 17-9 is reproduced here as FIG. 63. Mallery makes it clear in his text that the pulses shown in his figures can be binary digital logic pulses.
Bi-directional communication usually means using the same method or type of signaling to send information back to the user or base station. However, other forms of communication can be employed to send back information. This is an important point in model railroading since the track is used for both power and signaling which can create an electrically noisy and low impedance environment that can make signaling from the locomotive more difficult. Therefore different types of signals, other than full voltage DCC type waveforms are often employed to communicate from the remote object (locomotive, rolling stock, turnouts, or accessories) to the base station or user. For instance, the Pacific Fast Mail (PFM) Company in about 1984 used a cam on-board the locomotive to change the impedance of an RF signal transmitted from the base station as the locomotive moved. This information was used to synchronize a chuff sound generated by the PFM sound module to play out through a speaker in the locomotive. In 1988, Lenz DCC decoders used electrical loading by the remote object, as an acknowledgement means where a current increase is detected in response to a query by the base station. In on-board locomotive sound systems developed by QSI in 1991, sound from the remote object was used as a communication medium. In this case, a series of clink or clank sounds were used as a code to indicate the locomotive's status. Later, when more on-board memory was available, recorded verbal messages were used to communicate to the user. Also, in March of 1991, the Trix company was issued a German patent using a motor pulse system to send digital bi-directional communication down the track. In 1993 the NMRA issued a draft Recommended Practice for acknowledgement pulses in operation mode using a 250 Khertz signal to provide acknowledgement on the contents of registers used in DCC decoders in Operation Mode. In 1999, Lionel introduced their Rail Scope™ Video Camera System, which sent back video information from cameras inside the locomotive down the track to a TV monitor at the control center. This provided a view of the layout that would be seen by a miniature engineer in the locomotive. Later Lionel demonstrated their video system with sound as well as video transmitted back from the locomotive. Methods for direct digital bi-communication through the rails has been discussed and documented by the NMRA working group since 1994. QSI's U.S. Pat. No. 4,448,142, column 37, lines 44-60, describes what would be needed to send information back down the track, and in particular mentions the need for “redundant data transmission and error correction techniques”. In March of 2000 a frequency based bi-directional system was introduced in Europe. AJ Ireland developed and was issued U.S. patents in 2001 and 2003 on a transponding technique that reports location of locomotives on a layout back to a receiver through a separate network and it does not appear that this information is transmitted back down the track to the base station. On Sep. 16, 2001, Bernd Lenz was issued his first patent on bi-directional communication and received his second patent on bi-directional in February 2005, which was demonstrated recently at the NMRA convention in Seattle in July of 2004 and has been available from the Zimo Company since 2003. The Lenz bi-directional communication current-loop method was formally proposed to the NMRA as a bi-directional DCC standard. Mike's Train House (MTH) introduced their spread-spectrum method of bi-directional communication, using a method long employed in the communication industries. MTH was issued a patent for their method in 2004. To date, no bi-directional communication system has been proposed for analog DC or conventional AC operation other than sending back EMF voltage to the controller.
Down Loadable Software Code and Downloadable Sounds:
Downloadable code was available in many embedded system products in the 1980's. In 1985 Microfield Graphics had a graphics card that required the operating code to be downloaded on power up. The development of FLASH memory in 1984 by Toshiba lead to embedded system products in 1988 that could retain downloaded software in system memory. Intel also announced FLASH memory in 1988.
It was a natural extension to employ downloading methods to embedded system within on-board model train electronics. Discussions regarding reprogramming and downloading software began in the late 1980's when microprocessor technologies were beginning to appear in model train products. The Lenz LE130 DCC decoder had pins on the circuit board to allow downloadable code in 1988. The QS-1 on-board sound system by QSI had long term memory that allowed programming through the track of behavioral parameters in 1991. In 1993, QSI filed a patent application (which became U.S. Pat. No. 5,448,142) that discussed downloading via a computer directly to on-board sound systems. In 1994, the NMRA issued a Recommended Practice to download data into DCC decoder equipped locomotives on the track in Service Mode into the decoders Long Term Memory. Also in 1994, North Coast Engineering advertised that their throttles and decoders could be upgraded through programming. As the price of FLASH memory became more affordable, complete downloading of code and sound became possible for model railroad products. In 1984, QSI specified a new Application Specific Integrated Circuit design that had provision for downloading both code and sound into on-board FLASH memory from an external programmer. Since the late 1990's, ESU, a German Company, has provided special programmer products to downloadable code and sounds from a PC directly to their decoders in the locomotive through digital transmission down the rails. Mike's Train House's has a patent on their method of downloading sounds and code directly through the track rails to specially equipped locomotives.
Analog Control: Analog or conventional train control uses variable DC on the track to control the speed of the train for most two-rail model trains or variable 50 or 60 hertz AC to control the speed of most three-rail trains. Power sources for DC are usually described as “power packs” while power sources for AC trains are called “transformers”.
The greatest technology advances in model train control have been in the area of digital control to operate remote control features. Different methods were employed for AC powered and DC power trains.
For many years, the only remote control signal for AC powered trains, besides interrupting the power for direction change, was a DC signal superimposed on the AC track power to blow a horn or whistle. In 1984 QSI filed U.S. Pat. No. 4,914,431 which described using the operating state of the locomotive along with applications of positive and/or negative DC voltages superimposed on the AC track voltage as remote control signals to expand the operational capability of conventional AC powered trains.
Lionel had previously used these plus and minus DC remote control signals superimposed on AC track to control only two features, the bell and the horn sounds in the locomotive. QSI introduced an on-board sound and train control product for three-rail AC powered trains called QS-1 in 1991 which also used plus and minus DC signals to operate the horn and bell sounds, but added programming capability, remote coil coupler operation, and a myriad of new remote control features, using the ideas described in QSI's U.S. Pat. No. 4,914,431 patent. The QS-1 system was modified in 1994 for Mike's Train House's ProtoSound system. QSI later added improved versions of their Sound and Train Control system called “QS-2” introduced in 1996, “QS-2+” in 1997, and “QS-3000” in 1999. In 1992, Dallee Electronics designed a Sound and Control add-on unit for AC powered trains and introduced it to AC operators in 1998 as the LocoMatic™. The LocoMatic sends digital information to the train to control the different features under AC conventional control.
Standard DC powered trains were even more limited in operation than AC powered trains. Before the 1990's, the only remote control capability was to change the direction of the locomotive by changing the polarity on the track. In September 1995, QSI was granted a patent (U.S. Pat. No. 5,448,142) for using a Polarity Reversal (PR) and Polarity Reversal Pulses (PRP's) as remote control signals along with the state of the locomotive for feature and train control of DC powered trains. This technique allows us to use standard power packs to control a variety of train control features without requiring the operator to buy additional equipment or learn a complicated new system. The end user could purchase a locomotive equipped with our Quantum electronic sound and train control electronic product, take it home, place it on his layout and be able to control his horn or whistle, bell, direction, Doppler effect, programming of locomotive behavior, etc. all from the throttle and reversing switch on his standard power pack. In addition, these locomotives also had DCC capability for advanced operation using a DCC command station.
The following invention is an extension of this concept of simple control for analog or conventional operation plus related inventions that provide a basis for a complete, simple and inexpensive model train and layout operating environment. This invention provides both backward compatibility as well as forward expandability for the model train industry.